Nano Express

Nanoscale Research Letters

, 6:185

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

AFM-assisted fabrication of thiol SAM pattern with alternating quantified surface potential

  • Bradley MooresAffiliated withDepartment of Physics and Astronomy, University of Waterloo
  • , Janet SimonsAffiliated withDepartment of Biology, University of Waterloo
  • , Song XuAffiliated withAgilent Technologies
  • , Zoya LeonenkoAffiliated withDepartment of Physics and Astronomy, University of WaterlooDepartment of Biology, University of Waterloo Email author 


Thiol self-assembled monolayers (SAMs) are widely used in many nano- and bio-technology applications. We report a new approach to create and characterize a thiol SAMs micropattern with alternating charges on a flat gold-coated substrate using atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). We produced SAMs-patterns made of alternating positively charged, negatively charged, and hydrophobic-terminated thiols by an automated AFM-assisted manipulation, or nanografting. We show that these thiol patterns possess only small topographical differences as revealed by AFM, and distinguished differences in surface potential (20-50 mV), revealed by KPFM. The pattern can be helpful in the development of biosensor technologies, specifically for selective binding of biomolecules based on charge and hydrophobicity, and serve as a model for creating surfaces with quantified alternating surface potential distribution.